Scraping lead-tainted soil from yards within “The Box” – a 21-square-mile area that took the brunt of emissions from the Bunker Hill Smelter’s smokestacks – took two decades and cost more than $50 million.
But the yard cleanup is officially done.
This summer, the Environmental Protection Agency signed off on the work, which involved more than 3,200 residences and businesses. To protect young children from ingesting lead dust, up to a foot of soil was stripped away and replaced with clean dirt.
The pollution was the legacy of a 1973 fire at the Bunker Hill Smelter’s bag house. Gulf Resources and Chemicals opted to keep the smelter running with damaged air pollution controls and later bypassed the equipment altogether. The smelter spewed out roughly a ton of lead every day for six months.
Other lead was deposited by the Coeur d’Alene River and local mines’ waste rock. Through the 1960s, the waste rock was crushed into gravel for road projects and used for fill, said Jan Olsen, who works on Coeur d’Alene Basin issues for the Idaho Department of Environmental Quality.
Some patches of soil had lead concentrations of 60,000 parts per million, Olsen said. One thousand parts per million is the intervention level to protect human health.
Before the cleanup work began in 1985, children living in Smelterville had average blood-lead levels of 65 micrograms per deciliter, said Jerry Cobb, a program manager with Panhandle Health District. By 2000, average blood-lead levels had dropped to 2 to 3 micrograms per deciliter, he said.
Lead is so toxic to the nervous system that blood-lead levels of 10 micrograms per deciliter or less can reduce young children’s intelligence, lead to hearing loss and behavioral problems, and disrupt development, according to the Centers for Disease Control and Prevention.
The majority of the cleanup work was paid for by the Upstream Mining Group, which includes Hecla Mining Co., Asarco and Sunshine Precious Metals.
To protect the barrier of clean soil, people must apply for a free permit from the Panhandle Health District before building additions or planting trees.
Though yard cleanup is complete within “the box,” it continues in other parts of the Coeur d’Alene Basin. So far, about 2,000 properties outside the box have had their topsoil replaced. Lead and arsenic testing this fall will determine the extent of the remaining work, said Terry Harwood, executive director of the Basin Environmental Improvement Commission.
A new hazardous-waste repository planned near Old Mission State Park is slated to take contaminated soil from yard cleanups in the basin. However, the 20-acre East Mission Flats Repository has attracted its share of controversy.
Hundreds of residents signed a petition opposing the repository’s location in the Coeur d’Alene River’s flood plain. Federal officials are investigating whether the public had adequate opportunity to comment on the project. EPA’s Office of Inspector General, an independent branch funded by Congress to conduct audits and investigations, expects to wrap up the preliminary stage of its research in October, said John Manibusan, a spokesman.